The airplane appears to have been in a cruising position and flown straight into the mountain, said Richard Parker, an air safety investigator with the National Transportation Safety Board.

"One of the scenarios we'll be looking at is disorientation," Parker said last night.

Parker said the pilot, Maui's Democratic Party chairman Robert McCarthy, took off between 8 p.m. and 8:30 p.m. Friday.

The Coast Guard said it received a signal from the airplane's emergency transmitter at about 8:40 p.m.

The four other victims were Maui Councilman Thomas Morrow, council candidate Alfred Deloso, Maui's Democratic Party corresponding secretary Mitchell Katz and his wife, Suzanne.

Parker said the flaps on the twin-engine Piper Seneca PA-34 were not in a position that would indicate it was trying to climb above the mountain.

Parker said visibility was poor because of heavy rain.

"We have a report from a resident in the area that it was raining intensely," Parker said.

"This is a very dark area, very little lighting."

Parker said investigators have not determined whether McCarthy was flying by instruments or by visual references.

But Parker said McCarthy had not filed a notice with federal officials that he would be flying by navigational instruments.

Investigators will be looking at a log book to see if the airplane was maintained for instrument flight.

Parker and three Federal Aviation Administration investigators along with representatives of the engine and aircraft manufacturers spent yesterday at the crash site in a dense forested area above Halawa Valley.

The airplane, which has a cruising speed of 170 miles an hour, struck the trees on the side of the mountain at about 1,600 feet above sea level.

The crash site was roughly 200 feet below the top of the ridge, Parker said.

The aircraft cut a swath 30 to 50 feet wide and 170 feet long.

"As it hit the trees it just shed parts and came apart," Parker said.

Investigators plan to reconstruct the airplane today on level ground below the accident site.

Parker said investigators will be examining recording instruments and the engine tomorrow.

He said the investigation will take several weeks.

He said investigators will be reviewing a number of factors that may have contributed to the crash, including the pilot, aircraft and weather.